TIOCSTI: Document CAP_SYS_ADMIN behaviour in Kconfig

Clarifies that the LEGACY_TIOCSTI setting is safe to turn off even
when running BRLTTY, as it was introduced in commit 690c8b804ad2
("TIOCSTI: always enable for CAP_SYS_ADMIN").

Signed-off-by: Günther Noack <gnoack3000@gmail.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Link: https://lore.kernel.org/r/20230808201115.23993-1-gnoack3000@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig
index 341abae..069de55 100644 (file)
--- a/drivers/tty/Kconfig
+++ b/drivers/tty/Kconfig
@@ -164,6 +164,9 @@ config LEGACY_TIOCSTI
          userspace depends on this functionality to continue operating
          normally.
 
+         Processes which run with CAP_SYS_ADMIN, such as BRLTTY, can
+         use TIOCSTI even when this is set to N.
+
          This functionality can be changed at runtime with the
          dev.tty.legacy_tiocsti sysctl. This configuration option sets
          the default value of the sysctl.